FACTORS INFLUENCING THE OUTCOME OF IN-VITRO FERTILIZATION WITH EPIDIDYMAL SPERMATOZOA IN IRREVERSIBLE OBSTRUCTIVE AZOOSPERMIA

Microsurgical epididymal sperm aspiration (MESA) and invitro fertiliza tion (IVF) were found to offer limited opportunity for fatherhood to 4 5 men with obstructive azoospermia, due principally to poor embryo imp lantation. Adequate sperm preparations were obtained in 46/50 treatmen t cycles (92%), with the best motility found in the caput epididymis i n 89% of cases. The mean fertilization rate was 11.2% and fertilizatio n occurred in 23 cycles (50%), with embryo transfer arising from 12/26 men with vas aplasia (CAV), 4/9 with genital tract obstruction (EV) a nd 7/11 with irreversible vasectomy (VV). The overall implantation rat e was low, 8.7% per embryo transfer (11.7% per 2-3 embryo transfers) a nd was not improved by Fallopian transfer. There were two pregnancies (4% per cycle), both in the EV group where embryo formation and implan tation (2/4, 50% per cycle) were optimum even though sperm preparation s were paradoxically inferior to the CAV and W groups. The spermatozoa retrieved in the two successful EV cycles were appreciably blood cont aminated. Analysis of the 21 failed embryo transfers showed delayed fe rtilization in 10 cycles, cystic fibrosis (CF) mutation or familial di sease in 7/12 CAV men and the W men were older (P < 0.001). A pregnanc y which miscarried arose from a case of Young's syndrome, a carrier of CF mutation DF508. Male factors could thus be implicated in the high embryo wastage of MESA cycles and might also be influencing implantati on in other NF procedures. Where feasible, male reconstructive surgery is preferable unless fertilization can be improved, possibly by speed ier retrieval techniques or by permitting sperm capacitation in vitro, but probably more effectively by micro-assisted insemination.